Vania



P. MACGAHAN ELECTRICAL PROTECTlVE DEVICE.

APPLICATION FILED FEB. Io. I9Ie.

Patented Sept. 2

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l INvENToR Paul Mac Gahan wITNI-:ssEs:\

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P. IVIACGAHAN. ELECTRICAL PROTECTIVE DEVICE.

APPLICATION FILED EEB. I0, I9I6- 1 ,3 14,825 Patented Sept. 2, 1919.

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WITNESSES INVENTOR F19 ATTORNEY Paul Mac Gahan.

P. MACGAHAN.

ELECTRICAL PROTECTIVE DEVICE.

APPLICATION FILED FEB. 10,]9l5- A 1 ,314,825. Patented Sept. 2, 1919.

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INVENTOR ATTORNEY P. MACGAHAN.

ELECTRICAL PROTECTIVE DEVICE.

APPLICATION FILED FEB. Io, 19m.

1,314,825. Immdsept. 2,1919.

4 SHEETS-SHEET 4.

WITNESSES INVENTOR Paul Mac Gahan.

-'/., Y l f ATTORNEY UNITED sTATEs PATENT oEEicE.

PAUL MAcGAI-IAN, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION 0F PENNSYL- VAN IA.

ELECTRICAL PROTECTIVE DEVICE.

l Specification of Letters Patent.

Patented Sept. 2, 1919.

Application led February 10, 1916. Serial No. 77,389.

To all whom it may concern.'

Be it known that I, PAUL MACGAHAN, a citizen ot' the United States, and a resident oi' Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electrical Protective Devices, of which the following is a specification.

My invention relates to electrical-protective devices and particularly to relays and relay systems that are employed for tripping circuit interrupters, or operating other devices, upon the occurrence of predeterv mined conditions.

One object of my invention is to provide a relay system of thel above indicated character that is adapted to trip a circuit interrupter when the energy and current trav-` ersing it are reversed and of a predetermined value, respectively.

Another object of my invention is to provide a reverse-energy relay for a system of the above indicated character that is disproportionately more responsive to low values of voltage than to high values of voltage.

Another object of my invention is to provide a reverse-energy vrelay having two relatively movable windings that are so disposed with respect to eachl other that one will not induce voltage in the other, and, consequently, the phase-angular relation of their voltages ,will not be displaced.

Another object of my invention is to provide a relay having a movable member that will not be attracted-by the magnetizable core member of the relay, and, consequently, will not vibrate at relatively high loads.

Another object of my invention is to provide 'a reverse-energy relay having an nnrestrained movable member that is adapted to move freely upon the application of a minimum force in either direction.

In the carrying out of my invention, I provide a relay system that comprises areverse-energy relay, a current relay and two series-connected switches which are adapted to be actuated by the respective relays for controlling the tripping of a circuit interrupter. The windings of the reverse-energy relay are so disposed with respect to each other that one does not induce a current in the other thus preventing the operation of the relay when current traverses one winding and not the other. A normally incandescent tungsten lamp is connected in circuit with the potential winding of the reverse-energy relay to cause it to be disproportionately more responsive to low values of voltage than to high values of voltage. The movable member of the reverse-energy relay is so4 unrestrained that it is adapted to. move freely upon the application of a minimum force in either direction, thus securing ei'ective operation when a short cir-- cuit or other disturbance on the system causes its voltage to decrease. The armature of the reverse-energy relay is not a conducting disk, as is the case in the ordinary reverse-energy relay of the induction type, and, consequently, the vibration caused by the attraction of the armature to the magnetizable core member at relatively high loads is precluded.

1 is a front elevational view of a combined reverse-energy relay and current-relay device embodying my invention; Fig. 2 is a side view, partially in elevation and partially in section, of the relay device shown in Fig. 1; Fig. 3 is a top View, partially in plan and partially in section, of the relay device shown in 'Figs 1 and 2; Figs. 4 and 5 are diagrammatic elevational and plan views, respectively, of the reverse-energy relay shown in Figs. 1, 2 and 3, and Fig. 6 is a diagrammatic view of a part of the relay system embodying my invention.

A typical system, in connection with which my present invention may be employed, comprises an alternating-current circuit 1 that is adapted to be interrupted by means of a circuit interruptor 2. The pril mary winding 3 of a current transformer@ is connected in series relation with one conductor of the circuit 1, and its secondary winding 5 is connected in a circuit comprising the windings 6, 7, 8 and'9 of a reverseenergy relay 10 and the winding 11 of a current relay 12. The primary winding 13 of a potential transformer 14 is connected in parallel relation to the conductors of the circuit 1 and its secondary winding 15 is connected in circuit with the potential winding 16 of the relay 10 and a' normally incandescent tungsten lamp 17.

The relay 10 comprises two stationary magnetizable core members 18 and 19 of substantially U-shape that are so disposed with respect to each other that their respective legs are adjacent but separated by air gaps 20 and 21. The windings (E, 7, 8 and 9 surround the legs of the core members 18 and 19, and they are so connected that their magnetic fiuxes are cumulative. The movable member of the relay 10 is mounted on a shaft 22 and comprises the winding 16 and a mutilated or segmental damping disk 23. A movable arm 24 is also mounted on the shaft 22 and is adapted to actuate a movable contact member. 25 that coperates with a stationary contact member 26. The damping disk 23 is adapted to extend between the poles of damping magnets 27 but is not adapted to extend into the air gaps 20 and 21. The winding 16 is so normally disposed with respect to the windings G, 7, 8 and 9 that no resultant current is induced therein, and, consequently, their phase-angular relation will not be distorted. The relay 12 comprises a magnetizable core member 28 having a central leg, two side portions that are spaced from the central leg at one end by air gaps and downwardly projecting portions that are spaced from the central leg by an air gap. The core member 28 may be constructed in accordance with the core member shown in copending application Serial No. 840,754, filed by William M. Bradshaw, May 25, 1914, and assigned to the 'VVe'stinghouse Electric and Manufacturing Company. The relay 12 is provided with a winding 29 that is connected to the primary winding 30 of a normally saturatable transformer 31, the secondary winding 32 of which is connected in circuit with the windings 33 that surround the downwardly extending portions of the magnetizable core member 28. A conducting disk or armature 34 is mounted upon a shaft 35 and is adapted to extend within the air gap between the downwardly extending portions and the central leg of the magnetizable core member 28. A movable arm 36 is also mounted upon the shaft 35 `and is adapted to actuate a movable contact member 37 that engages a stationary contact member 38. The saturata'ble transformer 31 is provided for controlling the operation of the relay 12 and is so proportioned that the time element of operation of the relay shall be substantially inversely proportional to the current traversing the circuit 1 up to predetermined current values and invariable or definite above these predetermined values, substantially as set forth in application Serial No. 771,888, filed by A. W. Copley and B. H. Smith, June 5, 1913, and assigned to the Westinghouse Electric and Manufacturing Company.

The contact members 25, 26, 37 and 38 are series connected in a circuit comprising a tripping coil 39 and a source of electromotive force 40. Since the movable arm 24 of the reverse-energy relay is adapted to cfi'cit cngagenientI of the contact members 25 and 26 when the energy reverses in the circuit 1, and, since the movable arm 3G of the relay 12 is adapted to effect engagement of the contact members 37 and 38 when the current traversing the circuit 1 reaches a predetermined value, it these two conditions occur simultaneously, the winding 39 is adapted to be energized to trip the circuit interrupter 2.

The armature 34 of the relay 12 is adapted to extend between the poles of permanent damping magnets 41 for the purpose of retarding its movement, and an adjustable spring 42 is provided for adjusting the op eration of the relay.

The relays 10 and 12 are mounted within a casing 43 that is provided with .a face plate 44 for observing the operation of the devices. The casing 43 is provided with legs and bolts for mounting the same on a switchboard or other suitable structure. However, my invention is not limited to the particular casing or form of mounting that is illustrated.

The conductors of the winding 16 are subjected to such fluxes from the windings 6, 7, 8 and 9 that no electromotive force is induced therein t-o distortthe phase angle of the current that is supplied by the transformer 14. That is, one side of the winding lies directly in the field of the windings G and 9 and the other side lies in the field of the windings 7 and 8. Thus, since the iiux that cuts one side of the winding is of opposite sign to that which cuts the other side, the resultant induced current in the winding 1G is zero. The movement of the winding 16 is very small, and, consequently, the windings are adapted to be so related under all conditions of its movement that their resultant mutual inductance is relatively low. Thus, when a relatively large load traverses the circuit 1, such as under short-circuit conditions, the relay will function properly as a reverse-energy relay, whereas, if the resultant mutual induction was not substantially Zero, one winding would induce sufficient current in the other to cause it to operate on excessive loads in the normal direction. Further, since no disk is provided between the magnetizable core members-18 and 19, no attraction of the movable member will obtain under short-circuit condi` ions, and the movable member willnoty virate.

Since the resistance of a tungsten filament increases with the temperature and varies almost instantaneously with the applied voltage, it will be seen that the lamp 17 will tend to cause disproportionately more current to traverse the winding 16 when the voltage across the circuit 1 is low than when the voltage across the circuit 1 is high. This is advantageous when the voltage of a circuit is reduced to a low value because of a short circuit or other disturbance. The movable member of the relay 10 is free to move in.

either direction. Hence,l it will be more responsive to a reversal of the energy than it would be if it were provided with a control spring.

While I have shown my invention with respect to a' particular structure, it will be understood that it is not so limited, but is adaptable to various modications, as set forthin the appended claims.

I Claim as my invention:

l. A relay system comprising unrestrained means freely responsive to 'the direction of flow of energy, independently movable means responsive to current, and electro-responsive means controlled by the simultaneous operations of the said means, said electro-responsive means being adapted to operate, only when the energy traversing the system is in the reverse of its normal direction and its current is of a predetermined value.

2. In a protective device for an electric circuit, the combination with an1 electro-responsive device, of a reverse-energy relay, an independently movable over-current relay, and means actuated by the relays for controlling the operation of the electro-responsive device when the energy traversing the circuit is reversed arid` its current is of a predetermined value. l

3. A relay comprising a stationary magnetizable member having two pole-pieces, windings therefor, and a rotatable member having a winding thereon, said rotatable member being adapted to be normally in such position with respect to the pole-pieces, and the windings of the poleepieces being so oppositely connected, that the resultant mutual inductance has a relatively low value.

4. A relay comprising a stationary magnetizable member having two pole-pieces, oppositely connected windings for the polepieces, a rotatable member movable in a plane parallel to the face of the pole-pieces, and a winding disposed on the rotatable member in such position that, under normal conditions, the voltage induced therein by one pole of the magnetizable member is neutralized by that induced by the other pole.

A relay comprising a stationary mag-- netizable member having two pole-pieces, oppositely connected windings for the pole pieces, a rotatable member movable in a plane parallel to the face of the pole-pieces, and a winding disposed on the rotatable member in such position that, under normal conditions, the mutual inductance between the stationary and movable windings has a relatively low value.

6. In an electric circuit, the combination with a circuit interrupter and a trip coil therefor, of two series-connected switches, a

freely movable reverse-energy relay forroperating one of the switches upon a reversal of energy, and a current relay for operating the other switch when the Current traversing the circuit reaches a predetermined value.

7. In an electric circuit, the combination with a freely movable reverse-energy relay, of a resistor connected in circuit with the potential winding of the reverse-energy relay for rendering it disproportionately more sensitive to relatively low voltages than to relatively high voltages.

8. In an electric circuit, the combination with a freely movable reverse-energy relay, of an incandescent lamp connected in circuit with the potential winding of the relay for rendering it disproportionately more sensitive to relatively low voltages than to relatively high voltages.

9. In an electric circuit, the combination with a reverse-energy relay, of a normally incandescent resistor connected in circuit with the potential winding of the relay for lrendering it disproportionately more sensitive to relatively low voltages than to relatively high voltages.

In testimony whereof, I have hereunto sulliscribed my name this 31st day of J an. 19 6.

PAUL MAcGAI-IAN. 

